Walter j



(No Model.)

W. J. ALLEN.-

VALVE FOR STEAM ENGINES.

No. 883,935, Patented-June 5, 1888.

fl bi Witroe sses.

WALTER J. ALLEN, OF SPRINGFIELD, OHIO, ASSIGNOR OF TWO-THIRDS TO PHILIP J. COLE AND LAWRENCE J. HICKEY, BOTH OF SAME PLACE.

VALVE FOR STEAM-ENGIN ES.

seacrncawzon forming part of Letters Patent No. 383,985, dated June 5. 1888.

Application filed September 8, i887. Serial No. 249,081. (No model.)

To all whom it may concern: ing, respectively, an exterior and an interior Be it known that I, WALTER. J. ALLEN, a or sectional view of the same, enlarged. citizen of the United States, residing atSpring- Like parts are indicated by similar letters field, in the county of Clark and State of Ohio, of reference throughout the several views. have invented certain new and useful Im- In the said drawings, A is the engine-cyl- 5 5 provements in Valves for Steam-Engines, of inder,and B the steam-chest or valve-chamber. which the following is a specification. The valve-chamber is bored out at each end to My invention relates to improvements in form valve-seats, about which .are circular valves for steam-engines; and it particularly cavities G, into which the cylinder-ports C [0 relates in its nature to that class of valves open. The central portion of the valve-cham- 60 known as balanced valves. ber B is preferably enlarged to form an ex- The objectof my invention is to provide a haust-chamber, D, which extends from one valve of novel construction, the operation of valve seat to the other and completely surwhich produces an automatic cushion at each rounds the middle portion of the valve.

end ofthe engine stroke by establishing adi The valve I form with piston shaped end 65 rect communication through the valve beportions, EE, adapted to fit the seats in said tween the back and front of the piston, thus chamber, and a reduced middle portion, E, creating a premature discharge or exhaust bcwhich passes through the exhaust-chamber D, fore the final exhaust takes place, this premaand connects the said piston or hearing por- 2 ture exhaust being adapted to transferthe ter- 'tions E E. The steam to supply the engine is 70 minal pressure from the back to the front of preferably admitted through suitable pipethe piston producing the cushion. connection to the respective ends of the valve- My invention consists in a cylindrical or chamber, and presses with equal force, but in piston-shaped valve adapted to lit at either opposite directions on each end of the valve,

end in a cylindrical chamber which communithus forming a balanced valve. The valve is 7 cates with the engine-cylinder through one of adapted to be reciprocated as the engine moves the ports by which the steam is admitted or by any of the well-known valve-gear heretofore exhausted to or from the said cylinder, the used for that purpose. As the valve travels said valve being reduced at the middle and back and forth, the end portions are adapted provided with a longitudinal opening which to uncover the cylinder-portsin suchamanner 80 connects at either end with a small circular that they shall alternately communicate with port in the periphery of the valve, adapted the exhaust-chamber D and the live steam in near the end of each stroke to register with the the ends of the valve-chamber B, and thus admain ports of theengine'cylinder, and thus cs mit and exhaust the steam in the ordinary 3 5 tablish a communication through the exhaustmanner. 8 chamber from one end of the cylinder to the Extending through the middle portion, E, other. of the valve is a longitudinal opening, a, which My invention further consists in various conconnects at either end to small circular ports b, structions and combinations of parts herein-- which extend outward to the periphery of the after described,and pointed out in the claims. piston-shaped ends E E. These small ports b 0 In the accompanying drawings, which form I) are so arranged with reference to the main a part of this specification, Figure l is a parcylinder-ports, thatjust prior to the final extial sectional view of the valvechamber and haust from either end of the cylinder, the said valve and so much of the enginecyliuder as is ports I) b are adapted to register with the main necessary to theunderstanding of my improved ports, as shown in Fig. 1, and thus establish a 9 5 valve and its operation. Fig. 2 is a, transdirect communication from the back to the verse sectional view of the same. Fig. 3 is a front of the engine piston, through which the longitudinal sectional view of the'same, showterminal pressure of the steam at the back of ing the valve removed; and Figs. 4 and 5 are the piston is transferred to the front thereof, detail views of the ends of the valve, showthus forming an automatic cushion for the said roe piston at the end of each stroke or while passing centers. The cushion thus formed, it will be seen, is dependent upon the terminal pressure of the steam in the cylinder after each stroke. The terminal pressure is dependent upon the work taxed upon the engine. Gonsequently the cushion will be automatically regulated to thelabor of the engine. In order that the automatic cushion may be effective,it should be used prior to the termination of the stroke and as soon as practicable after the ex haust from that side of the piston is closed. To accomplish this I make the exhaust side practically without lap that is, the small premature exhaust-ports b are placed in the ex haust side of the valve, and that portion of the valve is cut away, so as to leave practically no intervening space on the valve between the premature exhaust'ports b and the exhaustchamber of the valve. By this construction it will be seen that the premature exhaust which forms the automatic cushion is accomplished just before the main exhaust takes place, and the cushion produced in the opposite ends of the cylinder immediately after this end of the cylinderis closed. By this construction it will be seen that the exhaust becomes practically continuous, and the exchange is made just before the piston reaches the end of its stroke, thus permitting the piston to cushion on the terminal pressure.

I preferably provide the bearing portions E E of the valve with spring-rings c c, to prevent the leakage of steam from the steam to the exhaust side of the valve. The exhaust-chamber D, it will be seen, is quite large, and at fords a free and easy exhaust for the engine, the exhaust-opening F being provided from the said chamber to the exhaust-pipe proper.

Having thus described my invention, what I claim as new, and desire to secure by Letters Patent, isv 1. A cylindrical valve to each end of which the steam is admitted at an equal pressure, and having a reduced middle portion about which is formed an exhaustchamber, said valve being provided at either end with small circular ports in the periphery thereof and a longitudinal passage connecting said ports through the said exhaust, said ports being located on the exhaust end of said valve, said valve formed without lap between said ports and the exhaust-chamber, substantially as specified.

2. A balanced valve, substantially as set forth, havinga longitudinal passage provided at either end with small openings or ports adapted to register with the main cylinderports,said valve being formed without exhaust lap between the small openings or ports and the exhaust-chamber in said valve, whereby the terminal pressure ofeach piston strokeis trans ferred from the front to the back of the piston to produce an automatic cushion, substantially as set forth.

3. A cylindrical balanced valve provided with piston-shaped ends adapted to open and close the main ports, as described, the reduced central portion adapted to form the exhaustchamber with which the cylinder-ports are adapted to register as the valve moves in either direction, premature exhaust-ports in said piston ends connected together through said reduced central portion, said premature exhaust-ports being adapted to register with the main cylinder-ports without lap between the premature exhaust-ports and the main exhaust-ports, substantially as specified.

In testimony whereof I have hereunto set my hand this 5th day of September, A. D. 1887.

XVALTER J. ALLEN.

Witnesses:

CHASE STEWART, PAUL A. STALEY. 

